Ecology and distribution. Recorded on siliceous rocks, frequently on large boulders, particularly bird perches. Distributed across the northern hemisphere in northern regions (Figure 1). The species was first reported from North America by Thomson (1979) from Alaska but this material is a Buellia (Sect. Melanaspicilia) species. However, the record of Rinodina milvina is based on a specimen of A. cacuminum.

Discussion

Amandinea cacuminum is a rather distinctive species characterized by the dark brown fragmented thallus consisting of tumid verrucae with erratically inserted apothecia. The spores have been compared by Degelius (1939) to those of Rinodina pyrina but the spores of this species possess septal wall thickenings during early developmental stages which are lacking in A. cacuminum.

The discovery of a pigmented hypothecium in a number of specimens, the filiform conidia and the fact that the thalline margin is frequently incomplete suggests that the species belongs in Amandinea rather than Rinodina where it has previously been placed. One specimen, Scotter 33154 (WIS), has relatively few lecanorine apothecia and intergrades continuously with adjacent lecideine apothecia when they become indistinguishable from those of A. punctata (Hoffm.) Coppins & Scheidegger, except for thallus morphology and colour.

Ascal and molecular data confirm the need to transfer Rinodina cacuminum to Amandinea. Ramold et al. (1994) found the species to possess Bacidia-type asci characteristic of Amandinea species rather than Lecanora-type asci which define the genus Rinodina. Preliminary molecular results (Gert Helms, Gottingen, personal communication) also aligns the species with Amandinea rather than Rinodina.